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1.
ACS Pharmacol Transl Sci ; 7(3): 863-877, 2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38481680

ABSTRACT

Colon cancer is among the most lethal and prevalent malignant tumors in the world, and the lack of effective therapies highlights the need for novel therapeutic approaches. Schisandrin B (Sch B), a lignan extracted from the fruit ofSchisandra chinensis, has been reported for its anticancer properties. However, to date, no studies have been done to characterize the exact molecular mechanisms underlying the antitumorigenic effects of Sch B in colon cancer. This study aimed to explore the antitumorigenic effects of Sch B in colon cancer and to understand the underlying therapeutic mechanism. A comprehensive analysis of the molecular mechanism underlying the antitumorigenic effects of Sch B on human colon cancer cells was performed using a combination of Raman spectroscopy, RNA-seq, computational docking, and molecular biological experiments. The in vivo efficacy was evaluated by a mouse xenograft model. Sch B reduced cell proliferation and triggered apoptosis in human colon cancer cell lines. Raman spectroscopy, computational, RNA-seq, and molecular and cellular studies revealed that Sch B activated unfolded protein responses by interacting with CHOP and upregulating CHOP, which thereby induced apoptosis. CHOP knockdown alleviated the Sch B-induced reduction in cell viability and apoptosis. Sch B reduced colon tumor growth in vivo. Our findings demonstrated that Sch B induced apoptosis and inhibited cell proliferation and tumor growth in vitro and in vivo. These results provided an essential background for clinical trials examining the effects of Sch B in patients with colon cancer.

2.
ACS Meas Sci Au ; 3(6): 434-443, 2023 Dec 20.
Article in English | MEDLINE | ID: mdl-38145020

ABSTRACT

Surface enhanced Raman scattering (SERS), since its discovery in the mid-1970s, has taken on many roles in the world of analytical measurement science. From identifying known and unknown chemicals in mixtures such as pharmaceutical and environmental samples to enabling qualitative and quantitative analysis of biomolecules and biomedical disease markers (or biomarkers), furthermore expanding to tracking nanostructures in vivo for medical diagnosis and therapy. This is because SERS combines the inherent power of Raman scattering capable of molecular species identification, topped with tremendous amplification in the Raman signal intensity when the molecule of interest is positioned near plasmonic nanostructures. The higher the SERS signal amplification, the lower the limit of detection (LOD) that could be achieved for the above applications. Therefore, improving SERS sensing efficiencies is vital. The signal reproducibility and SERS enhancement factor (EF) heavily rely on plasmonic nanostructure design, which has led to tremendous work in the field. But SERS signal and EF reproducibility remain key limitations for its wider market usability. This Review will scrutinize factors, some recognized and some often overlooked, that dictate the SERS signal and are of utmost importance to enable reproducible SERS EFs. Most of the factors pertain to colloidal labeled SERS. Some critically reviewed factors include the nanostructure's surface area as a limiting factor, SERS hot-spots including optimizing the SERS EF within the hot-spot volume and positioning labels, properties of label molecules governing molecule orientation in hot-spots, and resonance effects. A better understanding of these factors will enable improved optimization and control of the experimental SERS, enabling extremely sensitive LODs without overestimating the SERS EFs. These are crucial steps toward identification and reproducible quantification in SERS sensing.

3.
BMC Cancer ; 23(1): 174, 2023 Feb 21.
Article in English | MEDLINE | ID: mdl-36809974

ABSTRACT

BACKGROUND: Gliomas are the most common brain tumours with the high-grade glioblastoma representing the most aggressive and lethal form. Currently, there is a lack of specific glioma biomarkers that would aid tumour subtyping and minimally invasive early diagnosis. Aberrant glycosylation is an important post-translational modification in cancer and is implicated in glioma progression. Raman spectroscopy (RS), a vibrational spectroscopic label-free technique, has already shown promise in cancer diagnostics. METHODS: RS was combined with machine learning to discriminate glioma grades. Raman spectral signatures of glycosylation patterns were used in serum samples and fixed tissue biopsy samples, as well as in single cells and spheroids. RESULTS: Glioma grades in fixed tissue patient samples and serum were discriminated with high accuracy. Discrimination between higher malignant glioma grades (III and IV) was achieved with high accuracy in tissue, serum, and cellular models using single cells and spheroids. Biomolecular changes were assigned to alterations in glycosylation corroborated by analysing glycan standards and other changes such as carotenoid antioxidant content. CONCLUSION: RS combined with machine learning could pave the way for more objective and less invasive grading of glioma patients, serving as a useful tool to facilitate glioma diagnosis and delineate biomolecular glioma progression changes.


Subject(s)
Brain Neoplasms , Glioblastoma , Glioma , Humans , Spectrum Analysis, Raman/methods , Glycosylation , Glioma/pathology , Brain Neoplasms/pathology , Glioblastoma/pathology , Neoplasm Grading
4.
Clin Neuropsychol ; 37(5): 1025-1042, 2023 07.
Article in English | MEDLINE | ID: mdl-35317719

ABSTRACT

Objectives: The clock drawing test (CDT) is a widely used cognitive screening test. However, CDT performance is affected by education. This study examined an alternative, the Papadum test, designed for people with low levels of education/literacy. The association between education and test performance, correlation between CDT and Papadum test, and diagnostic accuracy of both CDT and Papadum tests were examined. Method: 89 healthy literate adults and 59 literate adults (all Bengali speaking) with a diagnosis of mild-moderate dementia from hospitals in Kolkata, India undertook the CDT and the Papadum test. Results: Education had a significant association with the CDT but not with the Papadum test. Across the whole sample there was a significant correlation between CDT and Papadum, but not within separate groups of healthy controls and patients. Diagnostic accuracy for the Papadum test was similar to that for CDT. Conclusions: Results highlight the strong influence that education has on CDT performance indicating that it is not suitable for those with low levels of literacy. The Papadum test could provide a viable alternative as a screening tool to the CDT for use with people who are illiterate or have low levels of education. Further validation studies are required.


Subject(s)
Dementia , Adult , Humans , Neuropsychological Tests , Educational Status , Dementia/diagnosis , Dementia/psychology , Literacy
5.
Nanotheranostics ; 6(3): 337-349, 2022.
Article in English | MEDLINE | ID: mdl-35721665

ABSTRACT

Detection of solid tumours through tissue- from depths relevant to humans- has been a significant challenge for biomedical Raman spectroscopy. The combined use of surface enhanced Raman scattering (SERS) imaging agents with deep Raman spectroscopy (DRS), i.e., surface enhanced deep Raman spectroscopy (SEDRS), offer prospects for overcoming such obstacles. In this study, we investigated the maximum detection depth through which the retrieval of SERS signal of a passively targeted biphenyl-4-thiol tagged gold nanoparticle (NP) imaging agent, injected subcutaneously into a mouse bearing breast cancer tumour, was possible. A compact 830 nm set-up with a hand-held probe and the flexibility of switching between offset, transmission and conventional Raman modalities was developed for this study. In vivo injection of the above SERS NP primary dose allowed surface tumour detection, whereas additional post mortem NP booster dose was required for detection of deeply seated tumours through heterogeneous animal tissue (comprising of proteins, fat, bone, organs, blood, and skin). The highest detection depth of 71 mm was probed using transmission, translating into a ~40% increase in detection depth compared to earlier reports. Such improvements in detection depth along with the inherent Raman chemical sensitivity brings SEDRS one step closer to future clinical cancer imaging technology.


Subject(s)
Metal Nanoparticles , Neoplasms , Animals , Bone and Bones , Gold/chemistry , Metal Nanoparticles/chemistry , Mice , Spectrum Analysis, Raman/methods
6.
Anal Chem ; 93(17): 6755-6762, 2021 05 04.
Article in English | MEDLINE | ID: mdl-33886282

ABSTRACT

Spatially offset Raman spectroscopy (SORS) is a technique for interrogating the subsurface composition of turbid samples noninvasively. This study generically addresses a fundamental question relevant to a wide range of SORS studies, which is how deep SORS probes for any specific spatial offset when analyzing a turbid sample or, in turn, what magnitude of spatial offset one should select to probe a specific depth. This issue is addressed by using Monte Carlo simulations, under the assumption of negligible absorption, which establishes that the key parameter governing the extent of the probed zone for a point-like illumination and point-like collection SORS geometry is the reduced scattering coefficient of the medium. This can either be deduced from literature data or directly estimated from a SORS measurement by evaluating the Raman intensity profile from multiple spatial offsets. Once this is known, the extent of the probed zone can be determined for any specific SORS spatial offset using the Monte Carlo simulation results presented here. The proposed method was tested using experimental data on stratified samples by analyzing the signal detected from a thin layer that was moved through a stack of layers using both non-absorbing and absorbing samples. The proposed simple methodology provides important additional information on SORS measurements with direct relevance to a wide range of SORS applications including biomedical, pharmaceutical, security, forensics, and cultural heritage.

7.
Anal Chem ; 93(7): 3386-3392, 2021 02 23.
Article in English | MEDLINE | ID: mdl-33573374

ABSTRACT

We propose a new method for estimating the reduced scattering coefficient, µs', of turbid homogeneous samples using Spatially Offset Raman Spectroscopy (SORS). The concept is based around the variation of Raman signal with SORS spatial offset that is strongly µs'-dependent, as such, permitting the determination of µs'. The evaluation is carried out under the assumptions that absorption is negligible at the laser and Raman wavelengths and µs' is approximately the same for those two wavelengths. These conditions are often satisfied for samples analyzed in the NIR region of the spectrum where SORS is traditionally deployed. Through a calibration procedure on a PTFE model sample, it was possible to estimate the µs' coefficient of different turbid samples with an error (RMSEP) below 18%. The knowledge of µs' in the NIR range is highly valuable for facilitating accurate numerical simulations to optimize illumination and collection geometries in SORS, to derive in-depth information about the properties of SORS measurements or in other photon applications, dependent on photon propagation in turbid media with general impact across fields such as biomedical, pharmaceutical, security, forensic, and cultural sciences.

8.
Analyst ; 145(23): 7623-7629, 2020 Nov 23.
Article in English | MEDLINE | ID: mdl-33000803

ABSTRACT

Spatially offset Raman spectroscopy (SORS) allows chemical characterisation of biological tissues at depths of up to two orders of magnitude greater than conventional Raman spectroscopy. In this study, we demonstrate the use of SORS for the non-invasive prediction of depth of an inclusion within turbid media (e.g. biological tissues) using only external calibration data sets, thus extending our previous approach that required internal calibration. As with the previous methodology, the concept is based on relative changes in Raman band intensities of the inclusion that are directly related to the path length of Raman photons travelling through the medium thereby encoding the information of depth of the inclusion. However, here the calibration model is created using data only from external measurements performed at the tissue surface. This new approach facilitates a fully non-invasive methodology applicable potentially to in vivo medical diagnosis without any a priori knowledge. Monte Carlo simulations of photon propagation have been used to provide insight into the relationship between the spatial offset and the photon path lengths inside the tissues enabling one to derive a general scaling factor permitting the use of spatial offset measurements for the depth prediction. The approach was validated by predicting the depth of surface-enhanced Raman scattering (SERS) labelled nanoparticles (NPs) acting as inclusions inside a slab of ex vivo porcine tissue yielding an average root mean square error of prediction of 7.3% with respect to the overall tissue thickness. Our results pave the way for future non-invasive deep Raman spectroscopy in vivo by enabling, for example, the localisation of cancer lesions or cancer biomarkers in early disease diagnosis and targeted treatments.


Subject(s)
Nanoparticles , Neoplasms , Animals , Calibration , Monte Carlo Method , Spectrum Analysis, Raman , Swine
9.
Adv Sci (Weinh) ; 7(15): 1903441, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32775148

ABSTRACT

Nanotheranostics, which combines optical multiplexed disease detection with therapeutic monitoring in a single modality, has the potential to propel the field of nanomedicine toward genuine personalized medicine. Currently employed mainstream modalities using gold nanoparticles (AuNPs) in diagnosis and treatment are limited by a lack of specificity and potential issues associated with systemic toxicity. Light-mediated nanotheranostics offers a relatively non-invasive alternative for cancer diagnosis and treatment by using AuNPs of specific shapes and sizes that absorb near infrared (NIR) light, inducing plasmon resonance for enhanced tumor detection and generating localized heat for tumor ablation. Over the last decade, significant progress has been made in the field of nanotheranostics, however the main biological and translational barriers to nanotheranostics leading to a new paradigm in anti-cancer nanomedicine stem from the molecular complexities of cancer and an incomplete mechanistic understanding of utilization of Au-NPs in living systems. This work provides a comprehensive overview on the biological, physical and translational barriers facing the development of nanotheranostics. It will also summarise the recent advances in engineering specific AuNPs, their unique characteristics and, importantly, tunability to achieve the desired optical/photothermal properties.

10.
Nanomaterials (Basel) ; 10(5)2020 May 14.
Article in English | MEDLINE | ID: mdl-32423172

ABSTRACT

Plasmon-coupled colloidal nanoassemblies with carefully sculpted "hot-spots" and intense surface-enhanced Raman scattering (SERS) are in high demand as photostable and sensitive plasmonic nano-, bio-, and chemosensors. When maximizing SERS signals, it is particularly challenging to control the hot-spot density, precisely position the hot-spots to intensify the plasmon coupling, and introduce the SERS molecule in those intense hot-spots. Here, we investigated the importance of these factors in nanoassemblies made of a gold nanorod (AuNR) core and spherical nanoparticle (AuNP) satellites with ssDNA oligomer linkers. Hot-spot positioning at the NR tips was made possible by selectively burying the ssDNA in the lateral facets via controlled Ag overgrowth while retaining their hybridization and assembly potential at the tips. This strategy, with slight alterations, allowed us to form nanoassemblies that only contained satellites at the NR tips, i.e., directional anisotropic nanoassemblies; or satellites randomly positioned around the NR, i.e., nondirectional nanoassemblies. Directional nanoassemblies featured strong plasmon coupling as compared to nondirectional ones, as a result of strategically placing the hot-spots at the most intense electric field position of the AuNR, i.e., retaining the inherent plasmon anisotropy. Furthermore, as the dsDNA was located in these anisotropic hot-spots, this allowed for the tag-free detection down to 10 dsDNA and a dramatic SERS enhancement of 1.6 × 108 for the SERS tag SYBR gold, which specifically intercalates into the dsDNA. This dramatic SERS performance was made possible by manipulating the anisotropy of the nanoassemblies, which allowed us to emphasize the critical role of hot-spot positioning and SERS molecule positioning in nanoassemblies.

11.
Small ; 16(10): e1906780, 2020 03.
Article in English | MEDLINE | ID: mdl-31997560

ABSTRACT

Optical theranostic applications demand near-infrared (NIR) localized surface plasmon resonance (LSPR) and maximized electric field at nanosurfaces and nanojunctions, aiding diagnosis via Raman or optoacoustic imaging, and photothermal-based therapies. To this end, multiple permutations and combinations of plasmonic nanostructures and molecular "glues" or linkers are employed to obtain nanoassemblies, such as nanobranches and core-satellite morphologies. An advanced nanoassembly morphology comprising multiple linear tentacles anchored onto a spherical core is reported here. Importantly, this core-multi-tentacle-nanoassembly (CMT) benefits from numerous plasmonic interactions between multiple 5 nm gold nanoparticles (NPs) forming each tentacle as well as tentacle to core (15 nm) coupling. This results in an intense LSPR across the "biological optical window" of 650-1100 nm. It is shown that the combined interactions are responsible for the broadband LSPR and the intense electric field, otherwise not achievable with core-satellite morphologies. Further the sub 80 nm CMTs boosted NIR-surface-enhanced Raman scattering (SERS), with detection of SERS labels at 47 × 10-9 m, as well as lower toxicity to noncancerous cell lines (human fibroblast Wi38) than observed for cancerous cell lines (human breast cancer MCF7), presents itself as an attractive candidate for use as biomedical theranostics agents.


Subject(s)
Antineoplastic Agents , Neoplasms , Photothermal Therapy , Surface Plasmon Resonance , Antineoplastic Agents/therapeutic use , Antineoplastic Agents/toxicity , Cell Line , Cell Survival/drug effects , Gold/chemistry , Humans , MCF-7 Cells , Metal Nanoparticles/chemistry , Nanostructures/chemistry , Neoplasms/therapy , Photothermal Therapy/instrumentation , Photothermal Therapy/methods , Spectrum Analysis, Raman , Surface Plasmon Resonance/instrumentation , Surface Plasmon Resonance/methods
12.
Chem Sci ; 11(33): 8671-8685, 2020 Jul 14.
Article in English | MEDLINE | ID: mdl-34123125

ABSTRACT

Numerous developments in optical biomedical imaging research utilizing gold nanostructures as contrast agents have advanced beyond basic research towards demonstrating potential as diagnostic tools; some of which are translating into clinical applications. Recent advances in optics, lasers and detection instrumentation along with the extensive, yet developing, knowledge-base in tailoring the optical properties of gold nanostructures has significantly improved the prospect of near-infrared (NIR) optical detection technologies. Of particular interest are optical coherence tomography (OCT), photoacoustic imaging (PAI), multispectral optoacoustic tomography (MSOT), Raman spectroscopy (RS) and surface enhanced spatially offset Raman spectroscopy (SESORS), due to their respective advancements. Here we discuss recent technological developments, as well as provide a prediction of their potential to impact on clinical diagnostics. A brief summary of each techniques' capability to distinguish abnormal (disease sites) from normal tissues, using endogenous signals alone is presented. We then elaborate on the use of exogenous gold nanostructures as contrast agents providing enhanced performance in the above-mentioned techniques. Finally, we consider the potential of these approaches to further catalyse advances in pre-clinical and clinical optical diagnostic technologies.

13.
J Biophotonics ; 13(1): e201960092, 2020 01.
Article in English | MEDLINE | ID: mdl-31595708

ABSTRACT

This work presents recent developments in spatially offset and transmission Raman spectroscopy for noninvasive detection and depth prediction of a single SERS inclusion located deep inside ex vivo biological tissues. The concept exploits the differential attenuation of Raman bands brought about by their different absorption due to tissue constituents enabling to predict the inclusion depth. Four different calibration models are tested and evaluated to predict the depth of surface enhanced Raman scattering labelled nanoparticles, within an up to 40 mm slab of porcine tissue. An external measurement carried out in transmission mode, with a noninvasively built model on the analysed sample, is shown to be insensitive to variations of the overall thickness of the tissue yielding an average root-mean-square error of prediction of 6.7%. The results pave the way for future noninvasive deep Raman spectroscopy in vivo enabling to localise cancer biomarkers for an early diagnosis of multiple diseases.


Subject(s)
Nanoparticles , Spectrum Analysis, Raman , Animals , Calibration , Swine
14.
Sci Total Environ ; 708: 134559, 2020 Mar 15.
Article in English | MEDLINE | ID: mdl-31761372

ABSTRACT

Agriculture in delta areas of emerging economies is highly reliant on the provision of water with adequate quality. This quality is often under pressure by season-related saltwater intrusion and poor domestic or industrial wastewater management. Methods to separate these two negative impacts on water quality for the delta areas are lacking but essential for proper management and supply of irrigation water. Therefore, the main aim of this research is to propose a method that maps salt and wastewater impacts on seasonal water quality and relate that to different land uses. Khulna, a delta city of Bangladesh was taken as a representative case study. Surface water samples have been collected from different city locations in winter, summer and monsoon seasons, and were analyzed for a variety of chemical-physical water quality parameters. Spatio-temporal variation maps were generated using Inverse Distance Weighted (IDW) interpolation method, and weighted overlay method was employed to map the current irrigation water use suitability based on FAO guidelines for the interpretations of water quality for irrigation. The influence of land-use on water quality was assessed by correlation analysis followed by bi-variate linear regression analysis. Analysis indicated significant (p < 0.05) seasonal dependent variation in water quality parameters, especially for saltwater influenced and generic water quality parameters. Also, the land-use percentage within 500 m radii to the sampling stations had a significant positive correlation with several parameters indicating saltwater and urban wastewater influences. Weighted overlay analysis revealed that during summer, approximately 1/3rd of the total studied area has a severe restriction for irrigation water use. The method presented here was shown to be effective in presenting variabilities on the effects of salinization and wastewater discharge on water quality in urbanized deltas and can be used as a knowledge base for formulating and implementing future urban infrastructure planning to improve irrigation water quality.

15.
Analyst ; 144(24): 7105-7129, 2019 Dec 02.
Article in English | MEDLINE | ID: mdl-31663527

ABSTRACT

Biomarkers are unquestionable biological indicators for diagnosis and therapeutic interventions providing appropriate classification of a wide range of health disorders and risk factors. Nonetheless, the detection and quantification of biomarkers need to be tested with sufficient reliability by robust analytical methods in order to assure clinical performance in health care settings. Since the analytical performance is determined by the sensitivity and specificity of the method employed, techniques have been intensively refined in order to avoid the misinterpretation of results and undesirable bias. Although biomarkers can be detected with the existing analytical techniques, to reproducibly quantify them in decentralized settings or remote locations with the required accuracy is still a challenge. Currently, only a few point-of-care devices for biomarker evaluation are commercially available. Thus, more focused research efforts are needed to overcome these limitations in order to provide universal patient-centered care platforms. To this end, plasmonic biosensors can be conveniently used as portable diagnostic devices for attaining timely and cost-effective clinical outcomes. The development of enhanced performance based on nanoplasmonics technology opens the way for sensor miniaturization, multiplexing and point of care testing. This review covers recent advances and applications of plasmonic and nanoplasmonic biosensors intended for biomarker diagnosis in clinical practice, including cancer, cardiovascular and neurodegenerative diseases. The review specially focuses on: (i) recent progress in plasmonics development including the design of singular nanostructured surfaces, (ii) novel chemical functionalization strategies for the appropriate incorporation of bioreceptors and (iii) plasmonic applications as real operative devices in the clinical field. Future prospects in the use of nanoplasmonic sensor platforms for personalised quantification and management of biomarkers directly in body fluids will also be discussed.


Subject(s)
Biomarkers, Tumor/analysis , Biosensing Techniques/methods , Surface Plasmon Resonance/methods , Animals , Biosensing Techniques/instrumentation , Cell Line , Diagnosis , Humans , Nanoparticles/chemistry , Neoplastic Cells, Circulating , Surface Plasmon Resonance/instrumentation
16.
Anal Chim Acta ; 1077: 232-242, 2019 Oct 24.
Article in English | MEDLINE | ID: mdl-31307714

ABSTRACT

Sepsis is a condition characterized by a severe stage of blood-infection often leading to tissue damage, organ failure and finally death. Fast diagnosis and identification of the sepsis stage (sepsis, severe sepsis or septic shock) is critical for the patient's evolution and could help in defining the most adequate treatment in order to reduce its mortality. The combined detection of several biomarkers in a timely, specific and simultaneous way could ensure a more accurate diagnosis. We have designed a new optical point-of-care (POC) device based on a phase-sensitive interferometric biosensor with a label-free microarray configuration for potential high-throughput evaluation of specific sepsis biomarkers. The sensor chip, which relies on the use of metallic nanostructures, provides versatility in terms of biofunctionalization, allowing the efficient immobilization of different kind of receptors such as antibodies or oligonucleotides. We have focused on two structurally different types of biomarkers: proteins, including C-reactive protein (CRP) and Interleukin 6 (IL6), and miRNAs, using miRNA-16 as an example. Limits of Detection (LoD) of 18 µg mL-1, 88 µg mL-1 and 1 µM (6 µg mL-1) have been respectively obtained for CRP, IL6 and miRNA-16 in individual assays, with high accuracy and reproducibility. The multiplexing capabilities have also been assessed with the simultaneous analysis of both protein biomarkers.


Subject(s)
C-Reactive Protein/analysis , Interleukin-6/analysis , MicroRNAs/analysis , Biomarkers/analysis , Biosensing Techniques/instrumentation , Biosensing Techniques/methods , Gold/chemistry , Limit of Detection , Microarray Analysis/instrumentation , Microarray Analysis/methods , Nanostructures/chemistry , Optical Devices , Point-of-Care Testing , Reproducibility of Results , Sepsis/diagnosis
17.
Anal Chem ; 91(14): 8994-9000, 2019 07 16.
Article in English | MEDLINE | ID: mdl-31246425

ABSTRACT

We propose an approach for the prediction of the depth of a single buried object within a turbid medium combining spatially offset Raman spectroscopy (SORS) and transmission Raman spectroscopy (TRS) and relying on differential attenuation of individual Raman bands brought about by the spectral variation of matrix absorption (and scattering). The relative degree of the Raman band changes is directly related to the path length of Raman photons traveling through the medium, thereby encoding the information on the depth of the object within the matrix. Through a calibration procedure with root mean square error of calibration (RMSEC) = 3.4%, it was possible to predict the depth of a paracetamol (acetaminophen) inclusion within a turbid matrix consisting of polyethylene (PE) by monitoring the relative intensity of two Raman bands of paracetamol exhibiting differential absorption by the matrix. The approach was shown to be largely insensitive to variations of the amount of the inclusion (paracetamol) and to the overall thickness of the turbid matrix (PE) with a root mean square error of prediction (RMSEP) maintained below 10% for the tested cases. This represents a major advantage over previously demonstrated comparable depth determination Raman approaches (with the exception of full Raman tomography requiring complex mathematical reconstruction algorithms). The obtained experimental data validate the proposed approach as an effective tool for the noninvasive determination of the depth of buried objects in turbid media with potential applications including determining noninvasively the depth of a lesion in cancer diagnosis in vivo.


Subject(s)
Acetaminophen/analysis , Spectrum Analysis, Raman/methods , Calibration , Polyethylene/chemistry
18.
Appl Spectrosc ; 73(12): 1428-1435, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31124368

ABSTRACT

Plasmonic nanoassemblies with amplified optical responses are attractive as chemo/bio sensors and diagnostic tracking agents. For real-life implementation, such nanostructures require a well-designed and controlled formation for maximizing the optical amplification. Forming these nanoassemblies typically requires numerous steps; however, the importance of the sequence of the steps is typically not discussed. Thus, here we have investigated the role of the sequence of tagging (or labeling, barcoding) of such plasmonic nanoassemblies with Raman active molecules in a quest to maximize the surface-enhanced Raman scattering (SERS) enhancement that could be achieved from the nanoassemblies. We have chosen the core-satellite nanoassembly arrangement to study the role of tagging sequence because it allows us to keep structural parameters constant that would otherwise influence the SERS amplification. We demonstrate that incorporating the tag molecule at an assembly point before formation of the nanojunctions leads to more tag molecules being positioned at the core-satellite nanojunctions, thereby resulting in higher SERS signal enhancement. This will thus prove to be a useful tool in fully utilizing the nanoassembly morphology generated hot-spot and maximizing its SERS performance.

19.
Ecotoxicol Environ Saf ; 176: 258-269, 2019 Jul 30.
Article in English | MEDLINE | ID: mdl-30939406

ABSTRACT

The rising threat of vector-borne diseases and environmental pollution has instigated the investigation of nanotechnology-based applications. The current study deals with a nanotechnological application involving the usage of nanometric pesticides such as permethrin nanoemulsion. The mean droplet diameter and zeta potential of the prepared permethrin nanoemulsion were found to be 12.4 ±â€¯1.13 nm and -20.4 ±â€¯0.56 mV, respectively. The temporal stability of permethrin nanoemulsion was found to be 4 days when checked in the external environment. The permethrin nanoemulsion exhibited LC50 values of 0.038 and 0.047 mgL-1 and 0.049 and 0.063 mgL-1 against larval and pupal stages of Culex tritaeniorhynchus and Aedes aegypti, respectively. The results obtained from the larvicidal and pupicidal assay were corroborated with the histopathological and biochemical profiles of hosts upon treatment with nanometric pesticide. Further, the biosafety studies of the nanopesticide were carried out against different non-target species like freshwater algae (Closterium), Cicer arietinum (Chickpea) and Danio rerio (Zebrafish), and the mosquitocidal concentration of nanopesticide was found to be non-toxic. The following study, therefore, describes the mosquitocidal efficacy of nanometric pesticide formulated in a greener approach, which can become a substitute for conventional pesticide application in an eco-benign manner.


Subject(s)
Aedes/drug effects , Culex/drug effects , Insecticides/chemistry , Mosquito Vectors/drug effects , Nanostructures/chemistry , Permethrin/chemistry , Animals , Colloids , Emulsions , Insecticides/pharmacology , Insecticides/toxicity , Larva/drug effects , Lethal Dose 50 , Nanostructures/toxicity , Permethrin/pharmacology , Permethrin/toxicity , Plant Extracts
20.
ACS Sens ; 4(1): 52-60, 2019 01 25.
Article in English | MEDLINE | ID: mdl-30525470

ABSTRACT

Existing clinical methods for bacteria detection lack speed, sensitivity, and, importantly, point-of-care (PoC) applicability. Thus, finding ways to push the sensitivity of clinical PoC biosensing technologies is crucial. Here we report a portable PoC device based on lens-free interferometric microscopy (LIM). The device employs high performance nanoplasmonics and custom bioprinted microarrays and is capable of direct label-free bacteria ( E. coli) quantification. With only one-step sample handling we offer a sample-to-data turnaround time of 40 min. Our technology features detection sensitivity of a single bacterial cell both in buffer and in diluted blood plasma and is intrinsically limited by the number of cells present in the detection volume. When employed in a hospital setting, the device has enabled accurate categorization of sepsis patients (infectious SIRS) from control groups (healthy individuals and noninfectious SIRS patients) without false positives/negatives. User-friendly on-site bacterial clinical diagnosis can thus become a reality.


Subject(s)
Bacteriological Techniques/methods , Blood/microbiology , Escherichia coli/isolation & purification , Interferometry/methods , Microscopy/methods , Point-of-Care Testing , Adsorption , Antibodies, Bacterial/chemistry , Antibodies, Bacterial/immunology , Bacterial Load/instrumentation , Bacterial Load/methods , Bacterial Proteins/chemistry , Bacteriological Techniques/instrumentation , Bioprinting , Escherichia coli/immunology , Gold/chemistry , Humans , Immunoassay/instrumentation , Immunoassay/methods , Interferometry/instrumentation , Microscopy/instrumentation , Nanostructures/chemistry , Protein Array Analysis/instrumentation , Protein Array Analysis/methods , Sepsis/blood , Sepsis/microbiology
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